add mention npub -> name autocomplete in comments

[alltheseas]

[alltheseas]

@ npub should render to corresponding name

1. before comment publication, and
2. after comment publication

@ NAME should also work (i.e. find npub/nprofile in the background)

[alltheseas]

example name autocomplete via damus

npubdamus.mp4

[abh3po]

yes, Multiple New Updates coming in on pollerama, I'll pick this up soon